def test_set_expression_bad(self):
potential = Potential(name='mypotential',
expression='a*x+b',
parameters={
'a': 1.0 * u.g,
'b': 1.0 * u.m
},
independent_variables={'x'})
with pytest.raises(ValueError):
potential.set_expression(expression='a*x**2+b*x+c')
def test_set_params_partial(self):
potential = Potential(name='mypotential',
expression='a*x+b',
parameters={
'a': 1.0 * u.g,
'b': 1.0 * u.m
},
independent_variables={'x'})
potential.set_expression(parameters={'a': 4.0 * u.g})
assert potential.expression == sympy.sympify('a*x+b')
assert potential.parameters == {'a': 4 * u.g, 'b': 1 * u.m}
def test_set_expression(self):
# Try changing the expression but keep the parameters
potential = Potential(name='mypotential',
expression='a*x+b',
parameters={
'a': 1.0 * u.g,
'b': 1.0 * u.m
},
independent_variables={'x'})
potential.set_expression(expression='a*x**2+b')
assert potential.expression == sympy.sympify('a*x**2+b')
assert potential.parameters == {'a': 1 * u.g, 'b': 1 * u.m}
def test_set_expression_and_params_mismatch(self):
potential = Potential(name='mypotential',
expression='a*x+b',
parameters={
'a': 1.0 * u.g,
'b': 1.0 * u.m
},
independent_variables={'x'})
with pytest.raises(ValueError):
potential.set_expression(
expression='c*x+d',
parameters={
'u': 1.0 * u.g,
'v': 1.0 * u.m
},
)
def test_setters(self):
new_potential = Potential()
new_potential.name = "SettingName"
new_potential.set_expression(
independent_variables=sympy.symbols({'r'}),
expression='r*sigma*epsilon',
parameters={
'sigma': 1 * u.nm,
'epsilon': 10 * u.Unit('kcal / mol')
}
)
assert new_potential.name == "SettingName"
assert new_potential.independent_variables == {sympy.symbols('r')}
assert new_potential.parameters == {
'sigma': 1 * u.nm,
'epsilon': 10 * u.Unit('kcal / mol')
}
assert new_potential.expression == sympy.sympify('r * sigma * epsilon')
def test_set_expression_and_params(self):
potential = Potential(
name='mypotential',
expression='a*x+b',
parameters={
'a': 1.0*u.g,
'b': 1.0*u.m},
independent_variables={'x'}
)
potential.set_expression(
expression='u*r+v',
parameters={
'u': 1.0*u.g,
'v': 1.0*u.m},
independent_variables={'r'}
)
assert potential.expression == sympy.sympify('u*r+v')
assert potential.parameters == { 'u': 1*u.g, 'v': 1*u.m}